Conventionally, development of an energy management system that performs optimum power management has been taking place in order to efficiently use power supplied from a plurality of power sources, e.g., power from a power system that supplies commercial power, power generated through photovoltaics, and power reserved in a battery.
For example, JP 3581699B discloses a configuration of a system that selects one of a power conversion apparatus and a secondary battery as a connection destination of a power generation system in accordance with power generated by the power generation system.
FIG. 1 shows an exemplary configuration of an energy management system.
As shown in FIG. 1, an energy management system 11 is formed by connecting a power control apparatus 12 to a power system 14 via an ammeter 13, and connecting a photovoltaic (PV) device 15 and an alternating current (AC) load 17 to the power control apparatus 12.
The power control apparatus 12 includes a PV-use DC/DC converter 21 and a DC/AC converter 22. An AC-side terminal of the DC/AC converter 22 is connected to the power system 14. On the other hand, a DC-side terminal of the DC/AC converter 22 is connected to the PV device 15 via the PV-use DC/DC converter 21. Hereinafter, wiring which is connected to the DC-side terminal of the DC/AC converter 22 and via which direct current power is supplied to and from the PV-use DC/DC converter 21 is referred to as a DC bus 23.
In the energy management system 11, the PV-use DC/DC converter 21 applies DC/DC conversion to power generated by the PV device 15 and supplies the resultant power to the DC/AC converter 22 via the DC bus 23, and then the DC/AC converter 22 applies DC/AC conversion to the supplied power and supplies the resultant power to the AC load 17. Excess power is supplied to the power system 14 (reverse power flow).
JP 3581699B is an example of background art.